Laserfiche WebLink
West Elk Mine <br /> <br />2.05-112 Rev. 06/05- PR10, 03/06- PR10, 05/06- PR10, 11/060- TR107, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11/10- MR372; 10/20- MR-452; <br /> 12/20- TR149; 12/21- TR150, 1/24-TR152, 2/25-MR486 <br />Mining of the longwall mining panels in the South of Divide mining area did not affect Minnesota <br />Reservoir. The reservoir is located outside the area of mining influence, using the most <br />conservative angle of draw. Measured ground subsidence nor seismicity caused by longwall <br />mining affected Monument Dam and Minnesota Reservoir. <br />Water Resources <br />Stock Watering Ponds and U.S. Forest Service <br />The stock watering ponds are typically located in debris flows or colluvium derived from the debris <br />flows (Dunrud 1989). Several stock watering ponds were mapped in the mining areas (for more <br />information see Section 2.2 of Exhibit 71 & 71A). Some of these ponds were also classified as U.S. <br />Forest Service water resources. The ponds in the permit area have been photographed on the ground <br />on an annual basis beginning in 2005. The debris flows consist of a heterogeneous mixture of clay <br />derived from the Wasatch Formation and boulders and gravels derived primarily from the Mount <br />Gunnison intrusive (granodiorites and quartz monzanites). Based on observations made during <br />geologic mapping in the area, these debris flows are even less likely to be affected by longwall mining <br />than the alluvium. The debris flows have a very low permeability and, because the clay matrix is <br />armored by the interstitial gravel and boulders, are resistant to erosion (the Deep Creek Ditch locally <br />flows in this material at steep gradients). Based on the above-mentioned observations, no effects are <br />expected when ponds in the South of Divide mining area are undermined. The clay-rich material that <br />lines these ponds is expected to provide a seal against any subsidence effects. Stock watering ponds <br />conditions will be surveyed, when accessible, before they are within twice the angle of draw. A <br />second survey will be conducted within three months after they are no longer in the angle of draw. <br />Stock ponds will be surveyed assuming climatic and ground conditions allow reasonable and safe <br />access for this and other monitoring. <br />No impacts to stock watering ponds in the Apache Rocks,Box Canyon West Flatiron, Sylvester <br />Gulch, SOD, Southern Panels, and Sunset Trail mining areas have been noticeably affected to date <br />when longwall mining occurred beneath them. <br />Streams and Ditches <br />The primary streams in the Southern Panels and Dry Fork mining areas are Dry Fork of Minnesota <br />Creek, Deer Creek, Poison Creek, and Lick Creek. South Prong Creek is in the Sunset Trail mining <br />area. The primary source of water to Minnesota Reservoir comes from the Deep Creek Ditch, <br />wherein a trans-basin diversion of water from the upper drainage of Deep Creek is transmitted to <br />Dry Fork. The Deep Creek ditch was constructed in debris flows or colluvium and alluvium <br />derived from the debris flow, as described above, this debris flow material is not expected to be <br />impacted by longwall mining. <br />As is also discussed in the most current versions of Exhibits 55B and 60E, the end of Deep Creek Ditch, <br />where it transitions into Dry Fork, lies above an area that was undermined by panel E5 gate entries. B seam <br />mining may also occur in this area. Annual Hydrology Reports submitted to the CDRMS each year <br />provide monitoring data and note potential impacts from mining.